Hi all, I''m building a whole new server system for my employer, and I really want to use OpenSolaris as the OS for the new file server. One thing is keeping me back, though: is it possible to recover a ZFS Raid Array after the OS crashes? I''ve spent hours with Google to avail.... To be more descriptive, I plan to have a Raid 1 array for the OS, and then I will need 3 additional Raid5/RaidZ/etc arrays for data archiving, backups and other purposes. There is plenty of documentation on how to recover an array if one of the drives in the array fails, but what if the OS crashes? Since ZFS is a software-based RAID, if the OS crashes is it even possible to recover any of the arrays? -- This message posted from opensolaris.org
On Fri, Feb 05, 2010 at 08:35:15AM -0800, J wrote:> To be more descriptive, I plan to have a Raid 1 array for the OS, and > then I will need 3 additional Raid5/RaidZ/etc arrays for data > archiving, backups and other purposes. There is plenty of > documentation on how to recover an array if one of the drives in the > array fails, but what if the OS crashes? Since ZFS is a > software-based RAID, if the OS crashes is it even possible to recover > any of the arrays?Sure, because the ZFS configuration is stored within the pool, not in the OS. Just install a new OS, attach the disks, and do a ''zfs import'' to find the importable pools. -- Darren
Ah, I see! Simple, easy, and saves me hundreds on HW-based RAID controllers ^_^ Thanks! -- This message posted from opensolaris.org
On 5-Feb-10, at 11:35 AM, J wrote:> Hi all, > > I''m building a whole new server system for my employer, and I > really want to use OpenSolaris as the OS for the new file server. > One thing is keeping me back, though: is it possible to recover a > ZFS Raid Array after the OS crashes? I''ve spent hours with Google > to avail.... > > To be more descriptive, I plan to have a Raid 1 array for the OS, > and then I will need 3 additional Raid5/RaidZ/etc arrays for data > archiving, backups and other purposes. There is plenty of > documentation on how to recover an array if one of the drives in > the array fails, but what if the OS crashes? Since ZFS is a > software-based RAID, if the OS crashes is it even possible to > recover any of the arrays?Being a software system it is inherently more recoverable than hardware RAID (the latter is probably only going to be readable on exactly the same configuration, and if the constellations are aligned just right, and the black rooster has crowed four times, etc). As Darren says, you can simply take either or both sides of the mirror and boot or access the pool on another ZFS-capable system. It doesn''t even have to use the same interfaces; last week I built a new Solaris 10 web server and migrated pool data from one half of a ZFS pool from the old server, connected by USB/SATA adapter. This kind of flexibility (not to mention data integrity) just isn''t there with HW RAID. --Toby> -- > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
On Fri, Feb 5, 2010 at 5:39 PM, A Darren Dunham <ddunham at taos.com> wrote:> Just install a new OS, attach the disks, and do a ''zfs import'' to find > the importable pools.The same behaviuor will be applied to move to another host the same ZFS pool (with the same or major ZFS version). I use this feature sometime to backup or store data on a big zpool (import, backup/copy/restore, export). Cesare -- Joan Crawford - "I, Joan Crawford, I believe in the dollar. Everything I earn, I spend." - http://www.brainyquote.com/quotes/authors/j/joan_crawford.html
On Sat, Feb 6, 2010 at 1:32 AM, J <jahservant13 at gmail.com> wrote:> saves me hundreds on HW-based RAID controllers ^_^... which you might need to fork over to buy additional memory or faster CPU :P Don''t get me wrong, zfs is awesome, but to do so it needs more CPU power and RAM (and possibly SSD) compared to other filesystems. If your main concern is cost, then some HW raid controller might be more effective. -- Fajar
Hi Cesare, If you want another way to replicate pools, you might be interested in the zpool split feature that Mark Musante integrated recently. You can read about it here: http://blogs.sun.com/mmusante/entry/seven_years_of_good_luck Cindy ----- Original Message ----- From: Cesare <voltsz at gmail.com> Date: Saturday, February 6, 2010 2:40 am Subject: Re: [zfs-discuss] Recover ZFS Array after OS Crash? To: zfs-discuss at opensolaris.org> On Fri, Feb 5, 2010 at 5:39 PM, A Darren Dunham <ddunham at taos.com> wrote: > > Just install a new OS, attach the disks, and do a ''zfs import'' to find > > the importable pools. > > The same behaviuor will be applied to move to another host the same > ZFS pool (with the same or major ZFS version). I use this feature > sometime to backup or store data on a big zpool (import, > backup/copy/restore, export). > > Cesare > > -- > > Joan Crawford - "I, Joan Crawford, I believe in the dollar. > Everything I earn, I spend." - > http://www.brainyquote.com/quotes/authors/j/joan_crawford.html > _______________________________________________ > zfs-discuss mailing list > zfs-discuss at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Hy Cindy, thanks for the hint. Nice feature, if I see that is not yet implemented on Solaris10 (i have on production system the Update8 for now). Right? Do you have a roadmap when this happen? By the way, having zpool with mirroring, I''ll try to follow the first part of Mark blog to have a second option (broke the mirror and attach to different server where there is a backup environment and then rebuild the mirror). Thanks. Cesare On Sat, Feb 6, 2010 at 6:04 PM, Cindy Swearingen <Cindy.Swearingen at sun.com> wrote:> Hi Cesare, > > If you want another way to replicate pools, you might be interested > in the zpool split feature that Mark Musante integrated recently. > > You can read about it here: > > http://blogs.sun.com/mmusante/entry/seven_years_of_good_luck > > Cindy > > > > ----- Original Message ----- > From: Cesare <voltsz at gmail.com> > Date: Saturday, February 6, 2010 2:40 am > Subject: Re: [zfs-discuss] Recover ZFS Array after OS Crash? > To: zfs-discuss at opensolaris.org > >> On Fri, Feb 5, 2010 at 5:39 PM, A Darren Dunham <ddunham at taos.com> wrote: >> > Just install a new OS, attach the disks, and do a ''zfs import'' to find >> > the importable pools. >> >> The same behaviuor will be applied to move to another host the same >> ZFS pool (with the same or major ZFS version). I use this feature >> sometime to backup or store data on a big zpool (import, >> backup/copy/restore, export). >> >> Cesare >> >> -- >> >> Joan Crawford ?- "I, Joan Crawford, I believe in the dollar. >> Everything I earn, I spend." - >> http://www.brainyquote.com/quotes/authors/j/joan_crawford.html >> _______________________________________________ >> zfs-discuss mailing list >> zfs-discuss at opensolaris.org >> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >-- Marie von Ebner-Eschenbach - "Even a stopped clock is right twice a day." - http://www.brainyquote.com/quotes/authors/m/marie_von_ebnereschenbac.html
On 06/02/2010 13:18, Fajar A. Nugraha wrote:> On Sat, Feb 6, 2010 at 1:32 AM, J<jahservant13 at gmail.com> wrote: > >> saves me hundreds on HW-based RAID controllers ^_^ >> > ... which you might need to fork over to buy additional memory or faster CPU :P > > Don''t get me wrong, zfs is awesome, but to do so it needs more CPU > power and RAM (and possibly SSD) compared to other filesystems. If > your main concern is cost, then some HW raid controller might be more > effective. > >any real data to back your claims? Then you need to be realistic - if ZFS consumes lets say 10-30% more CPU but still can do several GBs (assuming your storage can handle it) on a modern x86 box then for 99% of use cases where *much* less data is being actually handled by a fs in real workloads the difference in CPU usage in neglectable. This is even more so for fileservers (as in the OP case) where the box is usually dedicated to do a fileserving only. In real life in most environments, ZFS or not, the lvm/fs layer consume much less than 10% of your CPU on an entry level x86 server and if ZFS would consume a little bit more it doesn''t really matter. For example IIRC an old x4500 (older AMD CPUs) can do about 2GB/s sustained throughput when using ZFS while still not saturating CPUs. -- Robert Milkowski http://milek.blogspot.com
Hi Cesare, We anticipate that the zpool split feature will be available in an upcoming Solaris 10 release. Regarding the break mirror and import option, let me get back to you. I think we might have a bug in the current behavior. Thanks, Cindy On 02/06/10 15:44, Cesare wrote:> Hy Cindy, > > thanks for the hint. Nice feature, if I see that is not yet > implemented on Solaris10 (i have on production system the Update8 for > now). Right? Do you have a roadmap when this happen? > > By the way, having zpool with mirroring, I''ll try to follow the first > part of Mark blog to have a second option (broke the mirror and attach > to different server where there is a backup environment and then > rebuild the mirror). > > Thanks. > > Cesare > > On Sat, Feb 6, 2010 at 6:04 PM, Cindy Swearingen > <Cindy.Swearingen at sun.com> wrote: >> Hi Cesare, >> >> If you want another way to replicate pools, you might be interested >> in the zpool split feature that Mark Musante integrated recently. >> >> You can read about it here: >> >> http://blogs.sun.com/mmusante/entry/seven_years_of_good_luck >> >> Cindy >> >> >> >> ----- Original Message ----- >> From: Cesare <voltsz at gmail.com> >> Date: Saturday, February 6, 2010 2:40 am >> Subject: Re: [zfs-discuss] Recover ZFS Array after OS Crash? >> To: zfs-discuss at opensolaris.org >> >>> On Fri, Feb 5, 2010 at 5:39 PM, A Darren Dunham <ddunham at taos.com> wrote: >>>> Just install a new OS, attach the disks, and do a ''zfs import'' to find >>>> the importable pools. >>> The same behaviuor will be applied to move to another host the same >>> ZFS pool (with the same or major ZFS version). I use this feature >>> sometime to backup or store data on a big zpool (import, >>> backup/copy/restore, export). >>> >>> Cesare >>> >>> -- >>> >>> Joan Crawford - "I, Joan Crawford, I believe in the dollar. >>> Everything I earn, I spend." - >>> http://www.brainyquote.com/quotes/authors/j/joan_crawford.html >>> _______________________________________________ >>> zfs-discuss mailing list >>> zfs-discuss at opensolaris.org >>> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss > > >